Resize a video to 9:16 for YouTube Shorts

Turn a landscape or square video into a 9:16 vertical video for YouTube Shorts. You can crop it, add black bars and trim it, all in your browser.

No files are sent to any server

Open the SNS resize tool

Opens with the YouTube Shorts preset selected (9:16, 1080×1920, 3-minute limit).

SNS resize →

YouTube Shorts basics

YouTube's help says that videos uploaded on or after 15 October 2024 are counted as Shorts when they are square or vertical and 3 minutes or shorter. To turn a landscape video into a Short, you need to make it vertical or square. The SNS resize tool's YouTube Shorts preset outputs 9:16 at 1080×1920.

How to bring a landscape clip down to 9:16

Crop: Cut off the left and right sides to make it 9:16. The picture fills the whole frame, but a 16:9 video keeps only about a third of its width. This works best when the subject is in the center.
Letterbox: Shrink the whole frame and add black bars above and below. Captions near the edges stay in, but a 16:9 picture fills only about a third of the frame's height. YouTube's help recommends not adding padding or black bars to the video itself.

The tool you'll use

The SNS resize tool has presets for YouTube Shorts, TikTok, Instagram Reels and more. The preset you pick sets the output size. You can move the crop with the buttons or by dragging the preview. Tick "Letterbox / pillarbox (fit mode)" to add black bars instead of cropping. Everything runs in your browser.

The FFmpeg command

With FFmpeg, these commands make the same two versions.

Crop to fill 9:16 (center, no bars):

ffmpeg -i input.mp4 -vf "crop=ih*9/16:ih,scale=1080:1920,setsar=1" -pix_fmt yuv420p -c:a copy output.mp4

Fit the whole frame with bars (no crop):

ffmpeg -i input.mp4 -vf "scale=1080:1920:force_original_aspect_ratio=decrease,pad=1080:1920:(ow-iw)/2:(oh-ih)/2,setsar=1" -pix_fmt yuv420p -c:a copy output.mp4

crop=ih*9/16:ih keeps the full height and cuts out a center strip whose width is 9/16 of the height. setsar=1 makes the shape exactly 9:16; without it, a 1920×1080 video is stored with a shape slightly off 9:16. -pix_fmt yuv420p gives the format YouTube recommends (H.264 High Profile, 4:2:0). Without it, a 10-bit video such as an iPhone HDR clip becomes a different format called "High 10". -c:a copy copies the audio as it is, without converting it.

Steps

Click "SNS resize" above. The tool opens with the YouTube Shorts preset selected.
Choose your video.
If the subject isn't in the center, move the crop with the Crop position buttons or by dragging the preview.
If the video is longer than 3 minutes, shorten it to 3 minutes or less under Trim duration below.
Click "Resize for YouTube Shorts", then download the result.

Keeping the quality reasonable

Check the source resolution: Cropping a 1920×1080 video leaves about 600×1080 pixels. They get stretched to 1080×1920, so the result looks a little soft. Cropping a 4K (3840×2160) video needs no stretching.

Check that captions aren't cut off: Cropping removes the left and right sides of a landscape video. If captions near the edges get cut, add black bars instead.

FAQ

Q. What are the rules for YouTube Shorts?

A. YouTube's help says Shorts are up to 3 minutes long and have a square or vertical aspect ratio. This applies to videos uploaded on or after 15 October 2024.

Q. Should I crop or pad?

A. Cropping fills the whole frame but cuts off the left and right sides, so it suits videos with the subject in the center. Padding keeps everything, but the picture gets small. YouTube's help recommends not adding black bars to your video, so try cropping first and add bars only when captions at the edges get cut.

Q. Does it have to be exactly 1080×1920?

A. No. The conditions in YouTube's help are the length and the shape (square or vertical). Resolution isn't one of them, so a smaller 9:16 video such as 720×1280 is fine. Stretching a small video to a bigger size doesn't add detail, though.